The predictive processing hypothesis is a new unified theory of neural and cognitive function according to which our brains are prediction machines: they process the incoming sensory stream in the light of expectations of what those sensory inputs ought to be. On this view, only prediction errors are fed forward into the processing stream, and these are used to update subsequent predictions and guide action. In Surfing Uncertainty: Prediction, Action, and the Embodied Mind(Oxford University Press 2016), Andy Clark explains the theory from the perspective of embodied cognition, addressing such questions as how it alters the classical view of cognition as sandwiched between perception and action and how attention is employed to modulate the sensory flow. Clark, who is Professor of Logic and Metaphysics at the University of Edinburgh, also considers the current empirical support for the theory as well as its implications for traditional debates in epistemology, our understanding of schizophrenia and autism, and concerns about implicit bias.